Two Young Entrepreneurs Get Their Hands Dirty With Urban Farming An urban byproduct plants the seed for a big business.

Growing up: A Back to the Roots kit.

Photo © Ben Alsop

Nikhil Arora, 25, and Alejandro Velez, 24, didn't plan on being mushroom farmers. In 2009, during their last semester at the University of California, Berkeley, Arora lined up a corporate consulting job and Velez nabbed one in investment banking.

But a lecture on sustainability in a business ethics class changed all that. Their professor mentioned that he had heard it was possible to grow edible mushrooms in recycled coffee grounds.